安全头盔上的A与B标识是啥意思

https://kuaimiaobk.com.cn | https://app-x.dowtgx.org.cn/download.html | https://tool.kuaimiaor.com.cn/download.html | https://xtelegram.tgxdow.pro/download.html | https://www.tgxwin.com.cn | https://vpn.kuaimiaou.com.cn | https://heiytr.com.cn | https://ai.heiytx.com.cn | https://lucha-jsq.com.cn | https://m.lvchajsq.com.cn | https://tool.luchajsq.com.cn | https://vpn.kuaimiaot.com.cn | https://kuaimiaoae.com.cn | https://app.kuaimiaovpn.org.cn/download.html | https://user.office-bot.com.cn/download.html | https://ip.skylinejsq.com.cn/download.html | https://ip.skylinevpn.org.cn | https://xtelegram.tgxwin.com.cn/download.html | https://v6.skylinevpn.com.cn | https://win.heiyto.com.cn | https://www.gittgx.com.cn | https://app.officebot.org.cn/download.html | https://www.tgxdow.pro/download.html | https://vpn.kuaimiaoae.com.cn/download.html | https://win.skylinevpn.org.cn | https://app.skylineu.com.cn/download.html | https://excel.ai-office.org.cn/download.html | https://win.kuaimiaovip.com.cn | https://github.winpcx.com.cn/download.html | https://m.skylineip.com.cn | https://pc.kuaimiaot.com.cn | https://ios.luchaapp.com.cn | https://skylinevpn.org.cn/download.html | https://office-ai.com.cn/docs.html | https://ppt.office-ai.org.cn/download.html | https://tool.heiyta.com.cn/download.html | https://install.vip-kuaimiao.com.cn/download.html | https://tool.heiyto.com.cn/download.html | https://spe.skylinevpn.pro | https://v1.transocki.com.cn/download.html | https://win.skylineapp.com.cn/download.html | https://m.skylinewin.com.cn/download.html | https://v2.transocke.com.cn | https://tg-app.dowtgx.org.cn | https://tran.heiytr.com.cn/download.html | https://kuaimiaoce.com.cn/download.html | https://kuaimiaot.com.cn | https://app.heiytr.com.cn | https://dowtgx.org.cn/download.html | https://v6.ip-kuaimiao.com.cn |